Remove slider animation from the Volume Dialog

Slider steps animation will be fixed on the component side to match the
spec. This animation doesn't really fix anything now nor adds any value
without the Slider properly animating immediate steps

Flag: com.android.systemui.volume_redesign
Fixes: 395623147
Bug: 395578673
Test: manual on the phone. Adjust volume using physical buttons
Change-Id: I81334841561d32eb72eb02aff509a30584cfc383